Apparatus and method for automated non-contact eye examination

ABSTRACT

An eye measurement system includes an optical system. The eye measurement system is disposed in a housing which includes an aperture for providing light to and from the optical system and a subject&#39;s eye while the subject is separated and spaced apart from the housing, and the eye is not maintained in a fixed positional relationship with respect to the housing. An optical system movement arrangement moves the optical system. An automatic eye tracking arrangement ascertains a current positional relationship of the eye with respect to the optical system without human assistance, and in response thereto controls the optical system movement arrangement to move the optical system into a predetermined positional relationship with respect to the eye, for measurement of the eye, without human assistance. The eye measurement system can make objective, and/or subjective, refraction measurements of the eye.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority under 35 U.S.C. § 119(e) fromU.S. provisional patent application 63/048,946 filed on 7 Jul. 2020 inthe name of Thomas D. Raymond et al., the entirety of which is herebyincorporated by reference herein as if fully set forth herein.

BACKGROUND

In 2019, only about half of the people in the United States completedtheir recommended annual vision examination for a variety of reasonsincluding inconvenience, lack of transportation, lack of awareness ofeye health issues, and the high cost of eyeglasses; this in spite of thefact that 93 million adults in the United States are at high risk ofvision loss.

Similar trends are found internationally. In China, Japan, and Singaporeless than one third of patients receive annual comprehensive eye examsdespite the fact that an epidemic level of myopia progression in theAsia Pacific region poses a significant threat of visual impairment.

Furthermore, this rate may decline substantially in the future given theperceived risks of infection associated with routine eye examinations,especially in view of the worldwide COVID-19 pandemic and other possiblefuture pandemics. Risks are present through hand, body, and facialcontact with multiple ophthalmic instruments and chairs, and from theclose proximity to technicians and to other subjects or patients in thewaiting room.

During the pandemic, the American Academy of Ophthalmology and theAmerican Society of Retina Specialists recommended ophthalmologistsrestrict seeing patients to urgent and emergency cases and to screenincoming patients for the novel coronavirus. In the eye clinic, multipletraditional ophthalmic instruments are used in an eye exam, eachrequiring patient contact and thorough decontamination between patients.Patient workflow is reduced by clinical floor space limitations thathave driven most practices to tightly pack the necessary multipleinstruments into small examination rooms that are inherentlyinconsistent with social distancing. The reduced patient workflow andthe additional burden from implementing necessary protocols to seepatients have added to an already overly burdened patient workflow andserve to increase stress on health care providers (HCPs).

Post-COVID-19 pressures will be significant on Health Care Providers(HCPs) as well. As the ratio of practitioners to patients diminishes,these practices will need to be ever more efficient to handle theincreasing burden of eye care. These constraints immediately disqualifyvirtually all traditional single-purpose ophthalmic instruments andclearly beg for a new eye examination paradigm for this new era.

Fortunately, ophthalmology has been a national leader in telemedicineaugmented by technology and artificial intelligence. On Mar. 30, 2020,the U.S. Centers for Medicare & Medicaid Services released temporaryregulatory waivers and issued new rules for virtual visits using onlineapplications for billable telemedical services. In an April 2020 surveyof 1300 eye HCPs, 88% indicated that they already offer remote medicalexaminations, mostly through phone-based consultations, and 56%indicated that they had billed for telehealth services in the previousweek.

However, existing telemedicine approaches can only capture a subset ofthe tests required for a full eye exam. For example, while visual acuitytesting is possible without special equipment and can be used to verifya patient's current refractive prescription, without a refractionmeasurement it is not possible to alter that prescription or to providea new patient a prescription. A refraction measurement typicallyrequires refractive hardware and a skilled technician to operate it,hence tele-refraction is rarely available. For this reason, only 1.8% ofthose eye HCPs offer remote refractions. Finally, when asked “What wouldhelp you now?” the number one HCP response (64%) was “How to gear backup when re-opening.”

Furthermore, even if/when the COVID-19 pandemic subsides, there willcontinue to be a need for unattended and/or remotely-controlled eyeexamination equipment, for example to meet the eyecare needs in thirdworld and developing countries and in remote and rural areas whereaccess to in-person treatment is difficult. Also, in the case ofunattended remote kiosks, prevention or minimization of contamination ofthe equipment is especially important as there may be no one availableto clean, decontaminate or sterilize the equipment with any frequency.

Accordingly, it would be desirable to provide a system and method forautomated, non-contact, eye examination.

SUMMARY

As disclosed herein an apparatus comprises: a processing systemincluding a user interface; an eye measurement system including anoptical system, wherein the eye measurement system is configured to makeat least one optical measurement of an eye of a subject; a housinghaving the eye measurement system disposed therein, wherein the housingincludes an aperture for providing light to and from the optical systemand the eye while the subject is separated and spaced apart from thehousing and while the eye is not maintained in a fixed positionalrelationship with respect to the housing; an optical system movementarrangement which is configured to move the optical system; and anautomatic eye tracking arrangement which is configured to ascertain acurrent positional relationship of the eye with respect to the opticalsystem without human assistance, and in response thereto to control theoptical system movement arrangement to move the optical system into apredetermined positional relationship with respect to the eye withouthuman assistance. The eye measurement system includes: at least oneobjective refractive measurement device which is configured to make anobjective refraction measurement of the eye via the optical system, atarget, and a mirror system disposed in an optical path between the eyeand the target for extending a length of the optical path, wherein theoptical path further comprises at least one optical element of theoptical system. The processing system is configured to interact with thesubject via the user interface and in response to the interaction toadjust at least one parameter of the optical system to make a subjectiverefraction measurement of the eye based on the subject viewing thetarget.

In some embodiments, the housing conforms to 3A sanitary standards.

In some embodiments, the housing comprises an anti-microbial materialdisposed at an exterior surface thereof.

In some embodiments, the optical system movement arrangement isconfigured to move the optical system in two dimensions.

In some embodiments, the optical system movement arrangement isconfigured to move the optical system in three dimensions.

In some embodiments, the optical system includes a first lens, and theautomatic eye tracking arrangement includes a Lidar device which isconfigured to provide light to the eye via the first lens and to receivereturned light from the eye via the first lens for determining adistance between the eye and the first lens.

In some versions of these embodiments, the optical system includes apre-compensation section which is configurable to bring the target intofocus on the subject's eye for making the subjective refractionmeasurement of the subject's eye, and the distance between the eye andthe first lens as determined by the Lidar device is employed to adjust aposition of at least one lens in the pre-compensation section tomaintain focus and refractive correction for the eye.

In some embodiments, the automatic eye tracking arrangement comprises:at least one light source configured to illuminate the eye; and at leastone camera configured to receive an image of the eye, wherein the camerais configured to output image data of the image of the eye to theprocessing system, and wherein the processing system is configured tocontrol the optical system movement arrangement to move the opticalsystem into the predetermined positional relationship with respect tothe eye based on the image data.

In some embodiments, the apparatus includes a communication device,wherein the communication device is configured to communicate eyemeasurement data from the apparatus to an external remote terminal forevaluation.

In some versions of these embodiments, the communication device isconfigured to communicate the eye measurement data from the apparatus tothe external remote terminal via the Internet.

In some versions of these embodiments, the processing system isconfigured to execute a filtration algorithm for filtering the eyemeasurement data prior to communication to the external remote terminalto reject at least a portion of the eye measurement data when theportion of the eye measurement data is taken when the automatic eyetracking arrangement has not aligned the optical system to the eyewithin a specified level of accuracy.

In some versions of these embodiments, the apparatus, further comprises:at least one light source configured to illuminate the eye; and at leastone camera configured to capture images of the eye, wherein theprocessing system is configured to execute a filtration algorithm forfiltering the eye measurement data prior to communication to theexternal remote terminal to reject at least a portion of the eyemeasurement data when the portion of the eye measurement data is takenwhen the images of the eye fail to meet predefined quality criteria dueto at least one of: a full blink, a partial blink, an incorrect gazeangle, incomplete dis-accommodation, and a saccade.

In some embodiments, the optical system includes a pre-compensationsection which is configurable to bring the target into focus on thesubject's eye for making the subjective refraction measurement of thesubject's eye.

In some versions of these embodiments, the pre-compensation sectioncomprises one of: a set of discrete lenses, a Badal Optometer, BadalOptometer with Stokes cell, a variable focal length lens, a phase-onlyspatial light modulator, a deformable mirror and a retroreflectionrefractometer.

In some versions of these embodiments, the pre-compensation sectioncomprises the phase-only spatial light modulator, and the phase-onlyspatial light modulator is configured to compensate for tilt which isintroduced by head and eye motion by the subject.

In some embodiments, the at least one objective refractive measurementdevice includes one of: a Shack-Hartmann wavefront detector, a phasediversity sensor, a pyramid sensor, a curvature sensor, a point spreadfunction (PSF) sensor, and a retro illumination refractometer.

In some embodiments, the apparatus further comprises a display deviceprovided at an external surface of the housing, wherein the displaydevice is configured to provide information messages to at least one ofthe subject and an observer within sight of the display device.

In some embodiments, the at least one optical measurement of the eyeincludes at least one of: a high order aberration of the eye, a pupilresponse characteristic, an external image of the eye, intraocularpressure of the eye, a fundoscope image of the eye, a corneal topographyof the eye, an optical coherence tomography of the eye, and a blink rateof the eye.

In some embodiments, the apparatus further comprises a slit lampillumination source for enabling a slit lamp examination of the eye.

In some embodiments, the apparatus further comprises a structuredlighting device, wherein the structured lighting device is configuredfor at least one of: eye imaging, keratometry, eye motility testing, andslit lamp imaging of the eye.

In some embodiments, the structured lighting comprises a plurality oflight-emitting diodes arranged in a pattern around the aperture.

In some embodiments, the structured lighting comprises a video displaydevice.

In some embodiments, the structured lighting includes at least oneHelmholtz-like back-lit aperture.

In some embodiments, the user interface includes at least a microphonefor receiving voice communication from the subject, and a speaker forproviding audio information to the subject.

In some embodiments, the user interface includes at least one cameracapturing images of at least a portion of the eye, and an algorithmexecuted by the processing system for processing the captured images,for identifying at least one of eye blinks and gestures of the subjectin the captured images, and for interpreting the at least one of the eyeblinks, fixation gaze angle, facial and hand gestures as consciousfeedback from the subject. Additional unconscious cues such assquinting, and pupil dilation may also be used advantageously ininteracting with the patient.

In some embodiments, the user interface includes a camera for capturingimages of the subject and a display device for displaying images to thesubject.

In some embodiments, the apparatus further comprises: at least one lightsource configured to illuminate the eye; at least one camera configuredto capture images of the eye; and a visual cue generator for presentingto the subject a visual cue for changing a gaze angle of the eye whilecapturing the images of the eye.

In some versions of these embodiments, the camera is configured tocapture partial fundoscope images of a plurality of different portionsof the eye at a corresponding plurality of different gaze angles, andthe processing system is configured to stitch together the partialfundoscope images to produce a composite fundoscope image of the eye.

In some embodiments, the apparatus further comprises an air movementdevice which is configured to remove and dispose of airborne pathogensso as to prevent the airborne pathogens from contaminating theapparatus.

As also disclosed herein, an apparatus comprises: a processing systemincluding a user interface; an eye measurement system including anoptical system, wherein the eye measurement system is configured to makeat least one optical measurement of an eye of a subject; a housinghaving the eye measurement system disposed therein, wherein the housingincludes an aperture for providing light to and from the optical systemand the eye while the subject is separated and spaced apart from thehousing and while the eye is not maintained in a fixed positionalrelationship with respect to the housing; an optical system movementarrangement which is configured to move the optical system; an automaticeye tracking arrangement which is configured to ascertain a currentpositional relationship of the eye with respect to the optical system,and in response thereto to control the optical system movementarrangement to move the optical system into a predetermined positionalrelationship with respect to the eye; and a communication device,wherein the communication device is configured to communicate eyemeasurement data from the apparatus to an external remote terminal forevaluation. The eye measurement system includes: at least one objectiverefractive measurement device which is configured to make an objectiverefraction measurement of the eye via the optical system, a target, anda mirror system disposed in an optical path between the eye and thetarget for extending a length of the optical path, wherein the opticalpath further comprises at least one optical element of the opticalsystem. The processing system is configured to interact with the subjectvia the user interface and in response to the interaction to adjust atleast one parameter of the optical system to make a subjectiverefraction measurement of the eye based on the subject viewing thetarget. The communication device is further configured to receiveinstructions from the external remote terminal for adjusting at leastone operating parameter of the apparatus.

As further disclosed herein, a method comprises: making at least oneoptical measurement of an eye of a subject with an eye measurementsystem including an optical system, wherein the eye measurement systemis disposed within a housing, wherein the housing includes an aperturefor providing light to and from the optical system and the eye while thesubject is separated and spaced apart from the housing and while the eyeis not maintained in a fixed positional relationship with respect to thehousing; and ascertaining, via an automatic eye tracking arrangementwithout human assistance, a current positional relationship of the eyewith respect to the optical system, and in response thereto moving theoptical system into a predetermined positional relationship with respectto the eye without human assistance. Making the at least one opticalmeasurement of the eye includes: making an objective refractionmeasurement of the eye via the optical system, and interacting with thesubject via a user interface, and in response to the interactionadjusting at least one parameter of the optical system to make asubjective refraction measurement of the eye based on the subjectviewing a target through an optical path which includes a mirror systembetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system.

As still further disclosed herein, a method comprises: making at leastone optical measurement of an eye of a subject with an eye measurementsystem including an optical system, wherein the eye measurement systemis disposed within a housing, wherein the housing includes an aperturefor providing light to and from the optical system and the eye while thesubject is separated and spaced apart from the housing and while the eyeis not maintained in a fixed positional relationship with respect to thehousing; and ascertaining, via an automatic eye tracking arrangement, acurrent positional relationship of the eye with respect to the opticalsystem without necessary intervention from a human other than thesubject, and in response thereto moving the optical system into apredetermined positional relationship with respect to the eye withoutnecessary intervention from a human other than the subject. Making theat least one optical measurement of the eye includes: making anobjective refraction measurement of the eye via the optical system, andinteracting with the subject via a user interface and in response to theinteraction adjusting at least one parameter of the optical system tomake a subjective refraction measurement of the eye, without necessaryintervention from a human other than the subject, based on the subjectviewing a target through an optical path which includes a mirror systembetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system.

As yet further disclosed herein, a method, comprises: making at leastone optical measurement of an eye of a subject with an eye measurementsystem including an optical system, wherein the eye measurement systemis disposed within a housing, wherein the housing is disposed within anexamination room, and wherein the housing includes an aperture forproviding light to and from the optical system and the eye while thesubject is separated and spaced apart from the housing and while the eyeis not maintained in a fixed positional relationship with respect to thehousing; and ascertaining, via an automatic eye tracking arrangement, acurrent positional relationship of the eye with respect to the opticalsystem, and in response thereto moving the optical system into apredetermined positional relationship with respect to the eye without apresence of an ophthalmic technician in the examination room. Making theat least one optical measurement of the eye includes: making anobjective refraction measurement of the eye via the optical systemwithout the presence of the ophthalmic technician in the examinationroom, and interacting with the subject via a user interface and inresponse to the interaction adjusting at least one parameter of theoptical system to make a subjective refraction measurement of the eye,without the presence of the ophthalmic technician in the examinationroom, based on the subject viewing a target through an optical pathwhich includes a mirror system between the eye and the target forextending a length of the optical path, wherein the optical path furthercomprises at least one optical element of the optical system.

As even further disclosed herein, a method, comprises: making at leastone optical measurement of an eye of a subject with an eye measurementsystem including an optical system, wherein the eye measurement systemis disposed within a housing, wherein the housing includes an aperturefor providing light to and from the optical system and the eye while thesubject is separated and spaced apart from the housing and while the eyeis not maintained in a fixed positional relationship with respect to thehousing; and ascertaining, via an automatic eye tracking arrangement, acurrent positional relationship of the eye with respect to the opticalsystem, and in response thereto moving the optical system into apredetermined positional relationship with respect to the eye. Makingthe at least one optical measurement of the eye includes: making anobjective refraction measurement of the eye via the optical system, andinteracting with the subject via a user interface and in response to theinteraction adjusting at least one parameter of the optical system tomake a subjective refraction measurement of the eye based on the subjectviewing a target through an optical path which includes a mirror systembetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system. The method also includes: communicatingeye measurement data from the apparatus to an external remote terminalfor evaluation; and receiving instructions from the external remoteterminal for adjusting at least one operating parameter of the eyemeasurement system.

As yet even further disclosed herein an apparatus comprises: aprocessing system including a user interface; an eye measurement systemincluding an optical system, wherein the eye measurement system isconfigured to make at least one optical measurement of an eye of asubject; a housing having the eye measurement system disposed therein,wherein the housing includes an aperture for providing light to and fromthe optical system and the eye while the subject is separated and spacedapart from the housing and while the eye is not maintained in a fixedpositional relationship with respect to the housing; an optical systemmovement arrangement which is configured to move the optical system; andan automatic eye tracking arrangement which is configured to ascertain acurrent positional relationship of the eye with respect to the opticalsystem without a presence of an ophthalmic technician in the examinationroom, and in response thereto to control the optical system movementarrangement to move the optical system into a predetermined positionalrelationship with respect to the eye without a presence of an ophthalmictechnician in the examination room. The eye measurement system includes:at least one objective refractive measurement device which is configuredto make an objective refraction measurement of the eye via the opticalsystem, a target, and a mirror system disposed in an optical pathbetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system. The processing system is configured tointeract with the subject via the user interface and in response to theinteraction to adjust at least one parameter of the optical system tomake a subjective refraction measurement of the eye based on the subjectviewing the target.

As yet even further disclosed herein an apparatus comprises: aprocessing system having a user interface; an eye measurement systemincluding an optical system, wherein the eye measurement system isconfigured to make at least one optical measurement of an eye of asubject; a housing having the eye measurement system disposed therein,wherein the housing includes an aperture for providing light to and fromthe optical system and the eye while the subject is separated and spacedapart from the housing and while the eye is not maintained in a fixedpositional relationship with respect to the housing; an optical systemmovement arrangement which is configured to move the optical system; andan automatic eye tracking arrangement which is configured to ascertain acurrent positional relationship of the eye with respect to the opticalsystem without necessary intervention from a human other than thesubject, and in response thereto to control the optical system movementarrangement to move the optical system into a predetermined positionalrelationship with respect to the eye without necessary intervention froma human other than the subject. The eye measurement system includes: atleast one objective refractive measurement device which is configured tomake an objective refraction measurement of the eye via the opticalsystem, a target, and a mirror system disposed in an optical pathbetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system. The processing system is configured tointeract with the subject via the user interface and in response to theinteraction to adjust at least one parameter of the optical system tomake a subjective refraction measurement of the eye based on the subjectviewing the target.

BRIEF DESCRIPTION OF THE DRAWINGS

The example embodiments are best understood from the following detaileddescription when read with the accompanying drawing figures. Whereverapplicable and practical, like reference numerals refer to likeelements.

FIG. 1 illustrates a portion of an example embodiment of an automatednon-contact eye examination apparatus for examining the eye of asubject.

FIG. 2 illustrates another portion of an example embodiment of anautomated non-contact eye examination apparatus.

FIG. 3 illustrates an embodiment of an eye measurement system which maybe included in an eye examination apparatus.

FIG. 4 illustrates an example embodiment of an optical system which mayform part of an optical path for an eye measurement system.

FIG. 5 illustrates an example embodiment of an eye alignmentarrangement.

FIG. 6 illustrates elements of an example embodiment of anautorefractor.

FIG. 7 illustrates some principles of a pre-compensation section of aneye measurement system.

FIG. 8a , FIG. 8b and FIG. 8c illustrate an example embodiment of apre-compensation section of an eye measurement system.

FIG. 9 illustrates an example embodiment of an operation of a focus loopof the pre-compensation section of FIG. 8.

FIG. 10 illustrates an example embodiment of an operation of arefraction correction loop of the pre-compensation section of FIG. 8.

FIG. 11 illustrates an example embodiment of a pre-compensation sectionof an eye measurement system which is provided with a Light Detectionand Ranging (“LIDAR”) device.

FIG. 12 illustrates an external eye examination system using lightsources to provide illumination of the eye.

FIG. 13 illustrates an example embodiment of a structured lightingarrangement which may be used to illuminate the eye and to create newfixation directions to facilitate ocular measurements.

FIG. 14 illustrates an example embodiment of a slit lamp illuminator ofan eye measurement system.

FIG. 15 shows a bottom view of the slit lamp illuminator of FIG. 14.

FIG. 16 illustrates how an example embodiment of an eye measurementsystem may obtain a fundus image of an eye.

FIG. 17 illustrates an example of a fundus image of an eye.

FIG. 18 is a flowchart of an example embodiment of a method of automatednon-contact eye examination.

FIG. 19 illustrates an example of a web page which may be displayed on asubject's cell phone before, during and/or after an interaction with aneye examination apparatus.

FIG. 20 illustrates an example embodiment for a workflow for an eyeexamination of an eye.

FIG. 21 illustrates an example embodiment for a workflow for an eyeexamination apparatus to make a subjective (manifest) refractionmeasurement of an eye.

FIG. 22 illustrates an example embodiment of an eye target which may beused to communicate with a subject.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, example embodiments disclosing specific details are setforth in order to provide a thorough understanding of an embodimentaccording to the present teachings. However, it will be apparent to onehaving ordinary skill in the art having had the benefit of the presentdisclosure that other embodiments according to the present teachingsthat depart from the specific details disclosed herein remain within thescope of the appended claims. Moreover, descriptions of well-knownapparati and methods may be omitted so as to not obscure the descriptionof the example embodiments. Such methods and apparati are clearly withinthe scope of the present teachings.

FIG. 1 illustrates a portion of an example embodiment of an automatednon-contact eye examination instrument or apparatus 1000 for performingan eye examination of one or both eyes 15 of a patient or subject 10.Apparatus 1000 includes a housing 1100. As described in greater detailbelow, housing has an aperture 1110 for providing light to and from oneor more internal optical systems and one or both eyes 15 of subject 10while subject 10 is separated and spaced apart from housing 1100 andwhile eye 15 is not maintained in a fixed positional relationship withrespect to housing 1100. Here, an aperture may be defined as a spacethrough which light passes between instrument or apparatus 1000 and oneor both eyes 15 of subject 10. In some embodiments, aperture 1110 maycomprise a hole or opening in housing 1100. In some embodiments,aperture 1110 may comprise a protective, light-transmissive ortransparent, window through which light passes to and from one or moreinternal optical systems and one or both eyes 15 of subject 10.

Beneficially, the external surface of housing 1100 is smooth, allowingfor quick and easy disinfection. Beneficially, the external surface ofhousing 1100 conforms to 3A sanitary standards.

In some embodiments, housing 1100 is provided with protective sideshields 1120.

In some embodiments, an external surface of housing 1100 may befabricated of, and/or coated with, an anti-microbial material.

Apparatus 1000 further includes: cameras 1200; at least one opticalsystem 1300; an optical system movement arrangement 1400; an eye chart1500 as a target for eye(s) 15 of subject 10; and a mirror system 1600disposed in an optical path between eye 15 of subject 10 and the eyechart 1500. Mirror system 1600 lengthens an optical path between eye(s)15 of subject 10 and eye chart 1500, effectively providing a viewinglane for subject 10 to view eye chart 1500, and accordingly may bereferred to as a lane mirror arrangement. In some embodiments, apparatus1000 may include two optical systems; one for each of the two eyes 15 ofsubject 10. In some embodiments, apparatus 1000 may include two opticalsystem movement arrangements 1400; one for each optical system 1300 foreach of a subject's two eyes 15. In other embodiments, apparatus 1000may include one optical system movement arrangement 1400 which moves twooptical systems 1300.

FIG. 2 illustrates another portion of an example embodiment of anautomated non-contact eye examination apparatus 2000. Eye examinationapparatus 2000 may be one embodiment of eye examination apparatus 1000of FIG. 1. FIG. 2 illustrates that eye examination apparatus 2000includes optical system 1300, a processing system 2200, electronics2300, a display device 2400, a speaker 2500, a motor 2610 and a pulley2620. As with FIG. 1, automated non-contact eye examination apparatus2000 may include two optical systems; one for each of the two eyes 15 ofsubject 10.

Processing system 2200 may include one or more processors and memory,including volatile and/or non-volatile memory. The memory may storetherein instructions which may be executed by the one or more processorsto execute any of the various algorithms or methods disclosed below.

Motor 2610 and pulley 2620 may comprises one embodiment of opticalsystem movement arrangement 1400 of FIG. 1.

As shown in FIG. 2, eye examination apparatus 2000 may communicate toone or more external remote terminals via Internet 50. To that end,electronics 2300 may include a communication device (not shown) whichmay be wired and/or wireless and may communicate via WiFi, a wiredInternet connection, a wireless mobile network (e.g., 4G or 5G), etc.

Some of the significant features of eye examination apparatus 1000include the easily disinfected smooth outer shell or housing 1100 andthe notable absence of the traditional headrest for subject 10. Eyemeasurement apparatus 1000 provides light to and from optical system1300 and eye 15 of subject 10 while subject 10 is separated and spacedapart from housing 1100 and while eye 15 is not maintained in a fixedpositional relationship with respect to housing 1100.

That is, in contrast to traditional ophthalmic instruments, eyeexamination apparatus 1000 does not require the head of subject 10 beconstrained for eye measurements. Instead, eye examination apparatus1000 includes an automatic eye tracking arrangement which is configuredto ascertain a current positional relationship of eye 15 with respect tooptical system 1300 (beneficially without human assistance), and inresponse thereto to control optical system movement arrangement 1400 tomove optical system 1300 into a predetermined positional relationshipwith respect to eye 15 (again, beneficially without human assistance).The embodiment illustrated in FIG. 1 uses multiple cameras 1200 toautomatically and continuously align the internal measurement modules(e.g., optical system 1300) of eye examination apparatus 1000 to eye(s)15 of subject 10 during the measurements, regardless of normal subjectmotion. This concept eliminates the need for subject 10 to contact anysurfaces of eye examination apparatus 1000, or to be in proximity to atechnician during the measurements. Subject 10 does not even need to sitto have an eye examination.

Inside outer shell 1100, the use of spatial light modulators, amulti-function optical train, structured lighting, and head/eye trackinghardware may coordinate to provide subject 10 an experience that an eyeexamination is as simple as reading eye chart 1500. The optical pathsfor all measurements include a sufficiently large standoff,D_(STANDOFF), to allow all measurements to take place with subject 10standing comfortably distant from the protective window of aperture1110. The eye measurement system may be capable of video rate capturesof eye images and refraction measurements. Beneficially eye examinationapparatus 1000 has a small footprint which allows multiple eyeexamination apparati 1000 to be co-located in the typically smallexamination rooms found in eye clinics.

Audio/visual cues may be provided to the patient by the eye examinationapparatus 1000 and/or remotely by a technician or physician prior to,during, and/or after the eye examination. The added optional feature ofa remote telemedical connection may allow eye examination apparatus 1000to be conveniently located at places where it can be easily accessed bypatients or subjects, by pre-arranged appointment, during the course oftheir normal workday activities.

In the United States, a complete eye examination requires themeasurements and assessments shown in Table 1 below. Note that theIntraocular Pressure measurement is conducted to detect early-stageglaucoma, which may also be detected through fundoscopic examination.

TABLE 1 Test/Function Module Reason/Diagnosis Objective Refraction Auto-Detect uncorrected refractive error refractor Subjective Refraction Pre-Refine refraction for prescription Compensator Visual Acuity Eye DisplayTests spatial frequency response of central visual field Pupil FunctionEye Imager Tests eye monocular and binocular eye response to lightConfrontation Visual Eye Imager Tests peripheral visual system Fieldsresponse to moving objects Extraocular motility Eye Imager Testsstability of fixation and and alignment ability to smoothly trackobjects External (anterior) Eye Imager Detects pathologies of theeyelids Examination and tissues surrounding the eye, e.g., trachoma SlitLamp Exam Eye Imager Detects pathologies in the anterior segment andcornea, e.g., corneal opacity, cataract Fundoscopic Fundus Detectspathologies of the retina, Examination Imager e.g., age-related maculardegeneration, diabetic retinopathy Intraocular Pressure TonographerDetects glaucoma

In some embodiments, eye measurement apparatus 1000 is capable ofperforming all of the measurements and assessments listed in Table 1. Insome embodiments, eye examination apparatus 1000 is capable ofconducting remote refraction measurements without the presence of atechnician, thus enabling corrective prescriptions for eyeglasses orcontact lenses to be dispensed by a HCP immediately.

FIG. 3 illustrates an embodiment of an eye measurement system 3000 whichmay be included in an eye examination apparatus such as eye examinationapparatus 1000.

Eye measurement system 3000 includes a lane mirror system and an opticalsystem 3500, comprising optical devices and elements forming an opticalpath for eye measurement system 3000. Optical system 3000 is a specificembodiment of optical system 1300 of FIGS. 1 and 2.

FIG. 4 illustrates an example embodiment of an optical system 3000comprising various light sources, sensors (or detectors), viewingtargets, mirrors and other various optical elements forming an opticalpath for eye measurement system 3000. Optical system 3000 is a specificembodiment of optical system 3500 of FIG. 3, and will be described ingreater detail below.

FIG. 3 shows the entire optical path including lane mirrors M3, M4, M5and M6, eye chart display device LS5. All lane mirrors may be mounted tohousing 1100 so as to be stationary while LS5 is mounted to opticalsystem 3500 that is free to move both vertically and horizontally asnecessary to align itself to eye 15. The lane length is the opticaldistance between Image Plane 2 (shown in FIG. 4) and LS5. LS5 may beused to display traditional Snellen Eye Charts or similar targets uponwhich subject 10 may focus, as well as other icons or targets that mayserve as fixation targets to manipulate the gaze angle of subject 10.This optical arrangement allows the lane length to remain constant asoptical system 3500 is translated vertically. The lane length may becomparable to that used in traditional clinical lanes; e.g., 3 m orlonger. The lane mirrors are sufficiently wide (out of diagram plane) toreflect light from LS5 onto Image Plane 2 (and thus eye 15) regardlessof the horizontal position of optical system 3500. LS5 serves as the farrefraction target traditionally used to measure the distance refractioncorrection of eye 15 during subjective refraction; it also acts as thefixation target during objective refraction measurement. Additionally,the lane mirrors and LS5 may serve both eyes 15 when eye examinationapparatus 1000 is configured for binocular operation; such aconfiguration permits subject 10 to advantageously use convergence cuesto perceive the target at full lane distance to reduce the likelihood ofaccommodation. An optional near target, LS6 (as shown in FIG. 4), may bemounted onto optical system 3500 at a distance 30-50 cm from Image Plane2; by translating mirror M7 into the lane path, LS6 provides a neartarget for subjective and objective measurement of the near refractioncorrection for eyes 15 suffering from presbyopia.

Eye examination apparatus 1000 addresses two areas of criticalimportance that offer technical challenges: automated alignment andtracking of eye 15 required to achieve the needed optical alignmentwithout contacting subject 10; and providing an optical configurationwhich has a sufficient optical standoff to permit robust isolation ofeye examination apparatus 1000 and subject 10.

Regarding the former, in the past eye alignment has typically requiredthe head of subject 10 to be constrained while the eye measurementsystem is brought to the desired object plane and the x and y positions(e.g., pupil center). The object plane of the optical system istypically designed to be fixed focus relative to the body of theapparatus. Alignment is achieved by monitoring the x and y positions ofa desired fiducial while the z position is adjusted to bring the imageinto focus. Once alignment is achieved, one or a few measurement imagesmay be captured (e.g., Shack-Hartmann wavefront images).

In contrast, for embodiments of the automated eye examination apparatus1000, subject 10 is not required to be constrained and is subject tomotion in 6 dimensions: three positions and three angles. However,rather than design the automated alignment and tracking system to applyalignment corrections of eye examination apparatus 1000 in alldimensions, in some embodiments, variance is accommodated in the zdimension through proper optical design. In this case, optical system4000 may be already constrained to the distal side of the protectivewindow of aperture 1110. This may be accomplished through a variablefocus component. In some embodiments, alignment cameras 1200 are capableof detecting and measuring z distance, cyclo-rotation, and gaze anglevariations which can be used to compensate the measurements or to filterimages from the video stream that exceed the desired tolerances. Notethat the interpupillary distance must also be considered in thisbinocular instrument, however, this distance only need be adjusted atthe start of the measurement sequence. With these choices, an automaticeye alignment and tracking system simplifies to correcting only lateral(x) and vertical corrections (y) while measuring the remaining 4dimensions. The angle ranges measured are further bounded by providing avisual target for eye 15 to look at while being measured. Deviations mayoccur from saccadic movements which can be detected and excluded whennecessary.

In optical system 4000, eye tracking may be accomplished through theinclusion of a Light Detection and Ranging (“LIDAR”) device 4100 asdescribed in greater detail below with respect to FIG. 11.

FIG. 5 illustrates another example embodiment of an eye alignmentarrangement which incorporates cameras 1200. This optical system usestwo or more imaging cameras 1200 to provide 6-dimensional (e.g.,x,y,z,α,β,χ) position and rotation information of the position ofsubject 10 relative eye examination apparatus 1000 to permit accurate,real-time alignment of optical system 3500 to subject 10. Structured orunstructured lighting may optionally be supplied to improve the accuracyof the alignment. The two primary features to be tracked include the eyepupils. Cameras 1200 may be stationary with respect to eye examinationapparatus 1000, or may move with or independent of optical system 3500.Cameras may optionally be equipped with prisms 5100 to increase theoblique angles that can be captured.

Regarding the optical configuration, eye measurement system may includea variable phoropter/autorefractor, and an eye imaging arrangementincluding an imaging device (e.g., a camera) for imaging anterior andposterior segments of eye 15.

Manifest refraction is the gold standard for measuring refraction of eye15. FIG. 6 below illustrates an embodiment of eye examination apparatuswhich includes as a pre-compensation section 6100 a phoropter whichcomprises lenses that can be inserted into the line of sight of eye 15while subject 10 views a distant object (e.g., Snellen eye chart at 4meters distance). The physician may systematically vary the sphere valueand the cylinder magnitude and axis while asking subject 10 to comparebetween lens combinations as to which is clearer. Such subjectiverefraction generally may be first done monocularly, but ultimatelyverified binocularly. To ensure that subject 10 has relaxedaccommodation, additional plus lenses are often added to ensure thetarget becomes noticeably less focused. The lenses in the phoropter comein 0.25 Diopter increments, limiting the accuracy of measurement to whatis typically achieved in eyeglasses and contact lenses. Therepeatability of the measurement is limited to a standard deviation of0.319D by the subjective feedback and is highly dependent on the skillof the physician, particularly with respect to correcting the magnitudeand axis of the cylinder component.

FIG. 6 illustrates elements of an example embodiment of an autorefractor6000. Autorefractor 6000 includes, among other things, light source LS2,pre-compensation section 6100, beam splitters 6102 and 6104, a wavefrontsensor 6200, and lane mirror 6300.

In some embodiments, an autorefractor uses a Badal optometer aspre-compensation section 6100 through which subject 10 views an opticalfixation target. The target is conveniently projected into eye 15 with avergence at optical infinity or beyond (fogging) to stimulate subject 10into relaxing accommodation as when viewing an actual object at a largedistance. Light source LS2, having passed through the pre-compensationsection and the anterior of the eye focuses onto the patient's retinaand scatters backwards toward autorefractor 6000. Sensor 6200 (e.g., aShack-Hartmann wavefront detector, a phase diversity sensor, a pyramidsensor, a curvature sensor, a point spread function (PSF) sensor, aretro illumination refractometer, etc.) monitors the wavefront emanatingfrom “guide star light” injected into eye 15 and scattering from theretina that passes through pre-compensation section 6100, as discussedbelow with respect to FIGS. 7-11. Calibrated pre-compensating section6100, such as a Badal optometer, in the sensing branch serves tosubtract sphere and cylinder from the wavefront impinging on sensor 6200such that it remains within its measurement range. The total wavefrontfrom eye 15 is the sum of the pre-compensation values and the residualwavefront measured on sensor 6200. With each successive measurement ofthe wavefront, the pre-compensation section 6100 may be adjusted tofurther reduce the wavefront curvature. This iterative process continuesuntil the measured wavefront curvature it is within the desiredtolerance; the process may then terminate and the final refractionreported. Measurement precision approaching 0.1D is routinely obtainedwith properly designed autorefractors.

While the auto refractor affords better precision than manifestrefraction, traditional autorefractors seldom achieve the same level ofaccuracy as manifest refraction. The unnatural target projected at largeoptical distance does not effectively relax accommodation because othervisual cues of distance are missing. In particular, the autorefractor ismost often a monocular device that excludes convergence cues todistance; other cues can also make the subject perceive the targetcloser (e.g., looking into a small instrument or a small tube). Thesefactors frequently lead to “instrument accommodation” that can amount toa large fraction of a diopter of error. The cylinder magnitude and axis,on the other hand, are very accurately measured by an autorefractor.

In contrast to existing instruments, eye examination apparatus 1000 maysupport (simultaneous) manifest refraction and autorefractionmeasurements using the same optical system 1300, and both can becombined to yield higher accuracy results. In some embodiments,autorefractor 6000 incorporates corrective lenses positioned at avariable optical standoff of 150-200 mm and a real, dynamicallyprogrammable target (on an electronic display) at a distance presentedto the subject in binocular format. The distant real target mitigates“instrument accommodation” by subject 10. While similar to the manifestrefraction set up, this innovative approach raises challenges becausethe refractive correction is placed far from the normal spectacle plane(about 12.5 mm from eye vertex) where phoropter lenses would be placedand may introduce unwanted, unnatural optical distortions (e.g., tilt).Fortunately, the mathematics of ray tracing is well established, andthese distortions can be modelled and corrected. The corrective power ofthis pre-compensation section can be remotely adjusted in response tofeedback from subject 10. The refractive measurement from theautorefractor may be advantageously used to initially adjust thepre-compensation section prior to manifest refraction. With the finalcorrection in place, the HCP can conduct traditional subjective visualacuity testing much as they would with a phoropter, except that the lensadjustment for this scenario is electronically controlled. In this waythe advantages of the accuracy of a phoropter and manifest refractioncan be combined with the precision of the autorefractor. Indeed, eyeexamination apparatus 1000 may deliver both subjective refraction(manifest refraction) and objective refraction (autorefraction)measurements.

FIG. 7 illustrates some principles of a pre-compensation section of aneye measurement system.

The effective focal length, fcp, when located at the correction plane,at distance CP from eye 15, for a target at distance Lane, will bringthe target into best focus on the retina of the dis-accommodated eye 15.

Equation 1 below shows how the RoC, the radius of curvature of thewavefront at the corneal vertex, is related to fcp, CP, and Lane; RoC ispositive for hyperopes, negative for myopes, and infinity for a trueemmetrope.

$\begin{matrix}{\frac{1}{f_{cp}} = {{\frac{1}{{RoC} + {CP}} + \frac{1}{Lane}} = {Rx}_{cp}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

The measurement of RoC can be done at any convenient distance CP.

Lane is typically >3 meters in most eye clinics.

Given the RoC for each subject eye 15, the physician prescribesrefractive corrections, Rx_(cp), using Equation 1 with CP=0 for contactlenses and refractive surgeries, and to about 0.0125 meters foreyeglasses.

The purpose of the pre-compensation section is to compensate thesubject's refractive error (sphero-cylindrical) so the subject sees thetarget clearly. The effective focal length, f_(cp), of thepre-compensation section is adjusted to bring the target into focus wheneye 16 is dis-accommodated. Dis-accommodation may be accomplished bymanually fogging (as in manifest refraction) or with an interactivealgorithm (as in autorefractors). When eye 15 is dis-accommodated andthe sphero-cylindrical correction of the pre-compensation section hasbeen adjusted to produce best focus of the target for the subject, theradius of curvature (RoC) of the wavefront meridians just outside thecornea can be determined mathematically. The measured RoCs can then beused to prescribe the appropriate sphero-cylindrical refractivecorrection (e.g., contact lenses, eyeglasses, or refractive surgery) forsubject 10.

Various embodiments of pre-compensation may be accomplished with avariety of techniques. In its simplest embodiment, the pre-compensationsection may comprise a collection of lenses much like in a phoropter.Other embodiments include the incorporation of variable powerpre-compensation elements such as variable focal length lenses (e.g.,liquid lenses), a wide angle Badal optometer that employs moving opticson linear stages, variable mirrors (e.g., adaptive optics deformablemirror), a phase only spatial light modulator, or a retroreflectionrefractor, or combinations of the above.

In one such embodiment, a phase only spatial light modulator (SLM) maybe coupled with helper lenses to the same effect but with higher speedand with the ability to pre-compensate cylinder at any axis. The SLM iscapable of providing variable spherocylindrical correction over somedynamic range (e.g., ±5D), which can be added to the helper lens(es) tospan the relevant refractive correction range of human eyes (−16 to +8Dsphere, and 0 to −6D cylinder). Like the variable power options whichact to reduce the number of corrective lenses and mechanical complexitywhile improving the resolution of measurement below 0.25 diopters, theSLM introduces the ability to also correct for unwanted distortions suchas tip/tilt as the subject moves laterally. These variable power optionsalso can compensate for subject motion that introduces variations in theoptical standoff which would otherwise affect the measurement.

SLMs generally only supply about a 27c of phase delay but can do so atspatial resolutions approaching 4160(h)×2464(v) using 3.45 μm pixels atrefresh rates approaching 60 Hz. With this density, it is possible tocreate a variable power Fresnel lens with sphero-cylinder power up to ±5diopters over a 6 mm diameter aperture. Furthermore, the center of thiscorrection can be rapidly shifted to compensate for lateral eyemovement. The high refresh rate permits the apparent compensation ofchromatic aberration normally attributed to diffractive lenses when usedwith polychromatic targets. Color field sequential display rapidlysequentially displays the primary colors in the target while the subjectviews through corresponding corrected diffractive patterns; color fusionis accomplished in the human visual system.

The final power of the pre-compensating element can be mathematicallyconverted into a prescription for eyeglasses, contact lenses orrefractive surgery using simple paraxial ray tracing formulas likeEquation 1.

Returning to FIG. 4, FIG. 4 shows the schematic diagram of the opticalpath of eye measurement system 3000. Eye 15 is shown at the far left.

Light from light sources LS1, LS2, LS3, or LS4 may illuminate eye 15 andcreate reflected and scattered light that travels toward eye measurementsystem 3000 entering through aperture or window W1. L1 captures thislight and fully or partially collimates it for analysis. Light travelsthrough BS1 which may preferentially reflect wavelengths longer than 900nm and/or may be designed to preferentially reflect S polarized light;BS2 may transmit shorter wavelengths. As discussed in greater detailbelow with respect to FIGS. 8-11, optical system 4000 includes a relayimager comprising lenses L1 and L2 and a Badal optometer comprisinglenses L3 and L4 as a pre-compensation section which is configurable tobring the target into focus on eye 15 for making the subjectiverefraction measurement of the subject's eye 15.

LIDAR device 4100 may be fixed to lens L1; L1 may move to bring therelay imager into focus. L2 is the second lens of the relay imager andthis focusses the light from eye 15 onto a two-dimensional imagingsensor or camera IM1, positioned at Image Plane 1. BS2 is a partialreflector that allows light from eye 15 to reach IM1 to complete the eyeimaging section of optical system 4000.

The light reflected by BS2 travels through a Stokes Cell (“SC”), whichallows for continuously adjustable astigmatic correction; SC ispositioned at Image Plane 1 a which is equidistant from BS2 as ImagePlane 1. Spherical correction is accomplished with the Badal optometercomprised of lenses L3 and L4 and mirrors M1 and M2. Mirrors M1 and M3can be translated simultaneously to change the distance between L3 andL4, thereby providing continuously adjustable spherical correction. BS3is also a partial reflector for visible light and a high reflector fornear infrared (NIR) light. The transmitted visible light allows subject10 to view the eye chart; Image Plane 2 represents the optical positionof eye 15, with refractive correction applied, when viewing the targetsLS5 or LS6. The remaining visible and NIR light may be directed toward awavefront or similar sensor; a point spread function (PSF) sensor isshown in FIG. 4. Light is focused by lens L6, positioned at Image Plane2 a (equidistant from BS3 as Image Plane 2) onto imaging sensor IM2; thesize and shape of the formed spot can be analyzed to advantageously todrive the Stokes Cell and Badal optometer to correct for eye refractiveerrors.

Imaging sensor IM2 measures the radius of curvature of the wavefront oflight from eye 15 using well-known ‘guide-star’ techniques. Imagingsensor IM2 may include any of the following: a Shack-Hartmann Sensor, aPhase Diversity Sensor, a Pyramid Sensor, a Curvature Sensor, a pointspread function (PSF) Sensor, or a Retro-illumination refractometer.Additional lenses may be included as required to bring the scatteredwavefront onto the imaging sensor IM2 for proper measurement.

Light source LS2 may be a NIR super luminescent diode or LED thatprovides a narrow beam light (e.g., 2 mm diameter) collimated by lens L7and can be used to create a tight spot on the retina of eye 15 to act asa “guide star.” The output aperture for LS2 is positioned at Image Plane2 a to ensure that the light is imaged onto the Object Plane. LS3 is analternate light source which may be divergent in contrast to thatproduced by LS2; it may be used to flood illuminate the retina whenimaging the fundus. Like LS2, its output aperture may be approximately 2mm and is positioned at Image Plane 2 a. LS2 and LS3 may be physicallytranslated into position or optically or electronically switched.

FIGS. 8a, 8b and 8c illustrate an example embodiment of apre-compensation section 8000 of an eye measurement system, including arelay imager 8100 and a Badal optometer 8200.

This configuration has the advantage of providing a sharp eye image tomonitor eye alignment and the current eye state (e.g., open or closedeyelids) while measuring and providing a target with proper refractivecorrection to the subject. The target is not shown in FIG. 8 but wouldbe to the right of the position labelled Image Plane 2. FIG. 8aillustrates the nominal lens positions for a nominal position of eye 15relative to the optical system. FIG. 8b illustrates the lens positionswhen eye 15 is positioned further from the optical system than in FIG.8a . FIG. 8c illustrates the lens positions when eye 15 is positionedcloser to the optical system than in FIG. 8a . Note that the positionsof lenses L2 and L3 do not change.

In this embodiment, Relay Imager 8100 casts a sharp image of eye 15 atImage Plane 1 while Badal Optometer 8200 relays that image onto ImagePlane 2 while also adjusting the wavefront curvature to as to compensatefor the refractive error of eye 15. Relay Imager 8100 consists of twolenses, L1 and L2 of focal length f1 and f2, respectively. Relay Imager8100 will have its object plane a distance f1 from L1 and its imageplane at a distance f2 from L2. This produces an image with fixedmagnification −f2/f1 at Image Plane 1. The motion of eye 15 is trackedby translating lens L1 to maintain a distance of f1 to eye 15, thusensuring that a sharp image of eye 15 will always appear at Image Plane1 independent of the position of eye 15 relative to the optical system.The distance between L1 and eye 15 may be maintained by actuating theposition of L1 according to an autofocus algorithm or by directmeasurement the distance by using a LIDAR device or other distancesensor.

Badal Optometer 8200 similarly consists of two lenses, L3 and L4 withfocal lengths f3 and f4. A continuous range of refractive correction maybe applied to the wavefront curvature by adjusting the distance betweenL3 and L4. By advantageously placing an astigmatic correction device(e.g., a Stokes cell) at Image Plane 1, Badal optometer 8200 can correctfor both spherical and cylindrical refractive errors.

Relay Imager 8100 has the drawback that it may alter the wavefrontcurvature at Image Planes 1 and 2 depending on the separation between L1and L2. However, this correction is deterministic and can be compensatedthrough a small adjustment of the distance between L3 and L4 as shown inFIGS. 9 and 10.

FIG. 9 illustrates an example embodiment of an operation of a focus loop9000 of the pre-compensation section of FIG. 8. Focus loop 9000 may beimplemented by software stored in memory and which is executed by aprocessor, such as by processing system 2200.

Operation 9100 includes reading the position of eye 15 from LIDAR device4100.

Operation 9200 includes reading the current position of lens L1.

Operation 9300 includes subtracting the positions obtains in operations9100 and 9200 to obtain the eye-to-L1 distance.

Operation 9400 includes reading f1 (focal length of lens L1) fromcalibration data.

Operation 9500 includes subtracting f1 from the eye-to-L1 distance toobtain the tracking error for the position of lens L1.

Operation 9600 includes adding the tracking error to the currentposition of lens L1 to obtain a new target position for lens L1.

Operation 9700 includes moving lens L1 to the new target position.

Operation 9800 includes updating the current position of lens L1.

Operation 9900 includes providing the updated current position of lensL1 to the refraction correction loop of FIG. 10.

FIG. 10 illustrates an example embodiment of an operation of arefraction correction loop 10000 of the pre-compensation section of FIG.8. Refraction correction loop 10000 may be implemented by softwarestored in memory and which is executed by a processor, such as byprocessing system 2200.

Operation 10100 includes reading the refraction error from a wavefrontsensor.

Operation 10200 includes calculating the refractive correction to theposition of lens L4.

Operation 10300 includes obtaining the position of lens L1 from thefocus loop 9000.

Operation 10400 includes reading the position of lens L2 fromcalibration data.

Operation 10500 includes calculating a focus correction to the positionof lens L4 from the outputs of operations 10300 and 10400.

Operation 10600 includes reading the current position of lens L4.

Operation 10700 includes adding the refraction correction and the focuscorrection to the current position of lens L4 to obtain a new targetposition for lens L4.

Operation 10800 includes moving the lens L4 to the target position.

Operation 10900 includes updating the current position of lens L4.

FIG. 11 illustrates an example embodiment of a pre-compensation section11000 of an eye measurement system which is provided with LIDAR device4100.

The use of LIDAR device 4100 simplifies the control algorithm comparedto an autofocus algorithm by reducing the calculations required in eachcontrol iteration. Compact LIDAR devices 4100 are commercially availablewith a range and distance accuracy compatible with such an embodiment.In this case, LIDAR device 4100 can be mounted to move with L1 todirectly measure distance from L1 to eye 15. LIDAR device 4100 may alsobe advantageously optically positioned at Image Plane 1 or 2 to employthe optical system to ensure that only light reflected from the corneais used in the ranging. FIG. 11 illustrates how the light from LIDARdevice 4100 may be collimated with lens L5 and sent through L1 to focuson the cornea. In this case, lens L5, beam splitter BS1, and the LIDARunit may move with L1.

FIG. 12 illustrates an external eye examination system 12000 using lightsources to provide illumination of eye 15, for example for capturingimages of eye 15 using camera 12100.

Images of the exterior of eye 15 are useful for testing pupil function,external examination for pathologies of eye 15 and surrounding tissues,to test extraocular motility and alignment. Imaging of the anterior ofeye 15 with appropriate lighting from lighting elements 12200 may permitsome level of slit lamp examination. Finally, imaging of the posteriorof eye 15 allows examination of the fundus. In some embodiments, each ofthese imaging systems could be independently designed and simply mountedat a different location in the eye alignment and tracking system

Two or more cameras 12100 may supply video images of both eyes 15 totest pupil response, ocular motility, visual confrontation, and forexternal and internal examination of eyes 15 and nearby structures(e.g., eyelids).

Different visual stimuli may be applied through peripheral or coaxiallight sources for each examination element.

Light sources 12200 may be fixed relative to the field of view or maymove within it; some light sources may be structured (e.g., images offingers, or a narrow bright slit); some may be arranged in an array, asdescribed below with respect to FIG. 13.

In some embodiments, pre-compensation section 6100 of the optical systemmay be adjusted to obtain magnified images of the internal or externalarea of eye 15.

In some embodiments, pre-compensation section 6100 may be used toproduce an aerial image that is subsequently conditioned to match camera12100. The image can stay in focus despite changes in standoff distance;small magnification differences so introduced can be compensated in thedisplay of the image and in the quantitative analyses as well. The useof additional light sources 12200 can not only illuminate eye 15 andsurrounding tissue, but also can be used for keratometry and cornealtopography if desired. Light sources 12200 can also provide stimuli tothe subject for pupil and confrontation visual field and extraocularmotility and alignment testing. In some cases, lighting 12200 may becontrolled to smoothly translate across areas of the peripheral field ofview of subject 10. In a much similar way, slit lamp examination can besimulated with this same arrangement.

FIG. 13 illustrates an example embodiment of a structured lightingarrangement 13000 which may be used to illuminate eye 15 and to createnew fixation directions to facilitate ocular measurements.

Structured lighting may be used to illuminate eye 15 and to create newfixation directions to facilitate ocular measurements. Each dot in FIG.13 represents an individually addressable light source 13200. The ringpattern around aperture 13100 may be symmetrically disposed around theoptic axis of the optical system and may be used to illuminate eye 15for eye imaging and/or for keratometric measurement. The array ofperipheral light sources 13200 may be used for corneal topographicmeasurements and/or to test the integrity of the tear film surface whenactivated in concert, and/or can act as fixation points to change thegaze of subject 10 for slit lamp examination, for extraocular motility,and confrontation visual field testing.

FIG. 14 illustrates an example embodiment of a slit lamp illuminator14000 of an eye measurement system. The slit lamp illumination is frombelow eye 15 and utilizes a Kholer configuration. Light source LS4 isimaged onto projector lens L9 by condenser lens L8. The slit is createdelectronically on digital light processing chip, DLP, to formarbitrarily shaped apertures whose dimensions can be controlledelectronically with approximately 10 μm resolution and which can bechanged at video rates in synchrony with image captures on for exampleby processing system 2200. The slit illuminator assembly also comprisesa beam dump, BD1, which may absorb all unwanted light from LS4. Thisassembly is suspended above or below the LIDAR assembly and moves withthe optic assembly 3500 to maintain alignment with the eye as it moves.The slit lamp illuminator assembly may also rotate about a vertical axislocated at eye 15, as shown in FIG. 15, to allow an operator (e.g., aHCP controlling slit lamp illuminator from an external remote terminalvia a communication device of eye examination apparatus 1000) to changethe angle of incidence continuously over a range of ±60° from the opticaxis. Fine positioning of the light image on eye 15 can be accomplishedelectronically with the DLP. The observation angle for the scatteredlight can be adjusted by using a selected LED on LS1 to create afixation target upon which the subject can fixate, thereby rotating eye15 and thus the observation angle.

FIG. 15 shows a bottom view of the slit lamp illuminator of FIG. 14.

FIG. 16 illustrates how an example embodiment of an eye measurementsystem may obtain a fundus image of an eye.

Equation 2 below may be applied with respect to FIG. 16:

$\begin{matrix}{\frac{1}{f_{fundus}} = {\frac{1}{{RoC} + {CP}} + \frac{1}{Image}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

In some embodiments, a fundus imager may invoke different gaze anglesfor subject 10 using structured lighting 13200 to attain multiple imageswith a small field of view which can be stitched together into a highfield of view image of the fundus.

Fundus imaging also may benefit from the pre-compensation section of theoptical system, discussed above. In this case lighting is directed intoeye 15 and knowledge of the refractive state of eye 15 may simplifymaintaining focus. The case shown in FIG. 16 is essentially directophthalmoscopy where the lighting is directed through the nodal point ofeye 15 to illuminate a large section of the fundus. To obtain high anglecoverage of the fundus, subject 10 may be stimulated to gaze indifferent directions with lighting that creates a moving target whileimages are captured continuously. Processing system 2200 may employimage processing to undistort the images and then use fundus landmarksto stitch them into a large field of view fundus image.

FIG. 17 illustrates an example of a fundus image 17000 of eye 15 whichmay be obtained by eye examination apparatus 1000 and eye measurementsystem 3000 as discussed above with respect to FIG. 16.

In some embodiments, eye examination apparatus 1000 may include atonographer (not shown), and in that case the presence and progressionof glaucoma may be derived from tonographer measurements. In otherembodiments, fundoscopy of eye 15 allows the eye examination apparatus1000 to test for glaucoma of eye 15. Examples of a technique forglaucoma detection from a fundus image are disclosed in Shilpa SameerKanse, et al., “Retinal Fundus Image for Glaucoma Detection—A Review andStudy,” J. INTELL. SYST. 2017, the entirety of which is herebyincorporated by reference herein as if fully set forth herein.

FIG. 18 is a flowchart of an example embodiment of a method 18000 ofautomated non-contact eye examination.

An operation 18100 includes an eye examination apparatus ascertaining,via an automatic eye tracking arrangement, a current positionalrelationship of a subject's eye with respect to an optical system of aneye measurement system of the eye examination apparatus. Beneficially,this may be done without human assistance. In some embodiments,operation 18100 may track the positional relationships for both of asubject's eyes at the same time.

An operation 18200 includes the eye examination apparatus providinglight to and from the optical system and a subject's eye(s) while thesubject is separated and spaced apart from the housing of the eyeexamination apparatus and while the eye is not maintained in a fixedpositional relationship with respect to the housing. In someembodiments, operation 18200 may include providing light to and from theoptical system to both of a subject's eyes at the same time. In someembodiments, the eye measurement system may have two separate opticalsystems for the subject's two eyes, and in that case operation 18200 mayinclude providing light to and from each optical system to acorresponding one of the subject's eyes, for example at the same time.

An operation 18300 includes controlling an optical system movementarrangement of the eye examination apparatus to move the optical systeminto a predetermined positional relationship with respect to thesubject's eye(s). Beneficially, this may be done without humanassistance. In some embodiments, the eye examination apparatus may havetwo separate optical systems for the subject's two eyes, and in thatcase operation 18300 may include moving each optical system into apredetermined positional relationship with respect to a correspondingone of the subject's eyes.

An operation 18400 includes the eye examination apparatus making anobjective refraction measurement of a subject's eye via the opticalsystem. In various embodiments, operation 18400 may include making anobjective refraction measurement of a subject's eye via a Shack-Hartmannwavefront detector, a phase diversity sensor, a pyramid sensor, acurvature sensor, a point spread function (PSF) sensor, a retroillumination refractometer, etc. In some embodiments, the eyemeasurement system may have two separate optical systems and objectmeasurement devices for the subject's two eyes, and in that caseoperation 18400 may include the eye examination apparatus making anobjective refraction measurement of each of the subject's eyes via acorresponding optical system.

An operation 18500 includes the eye examination apparatus interactingwith the subject via a user interface, and in response to theinteraction adjusting at least one parameter of the optical system tomake a subjective refraction measurement of the subject's eye(s) basedon the subject viewing a target. Beneficially, the target may be an eyechart. Beneficially, subjective measurements may be made separately foreach eye, and a combined subject measurement may be made with thesubject viewing the target with both eyes at the same time.

An operation 18600 includes the eye examination apparatus making othermeasurements and/or examinations of the subject's eye via the opticalsystem, or both eyes in parallel via corresponding optical systems foreach eye. In various embodiments, these other measurements and/orexaminations may include measuring high order aberrations of the eye,determining intraocular pressure, performing a fundoscopic examination,performing a slit lamp examination, determining keratometry/cornealtopography/astigmatism, determining a pupil function, performingconfrontation visual field testing (e.g., peripheral vision test),and/or determining extraocular motility. In some embodiments, operation18600 may be omitted.

An operation 18700 includes the eye examination apparatusqualifying/filtering eye measurement data. In some embodiments, eyemeasurement data may be filtered to reject at least a portion of the eyemeasurement data when the portion of the eye measurement data is takenwhen the automatic eye tracking arrangement has not aligned the opticalsystem to the eye within a specified level of accuracy. In someembodiments, eye measurement data may be filtered to reject at least aportion of the eye measurement data when the portion of the eyemeasurement data is taken when the images of the eye fail to meetpredefined quality criteria due to at least one of: a full blink, apartial blink, an incorrect gaze angle, incomplete dis-accommodation,and a saccade. In some embodiments, operation 18700 may be omitted.

An operation 18800 includes communicating eye measurement data from theeye examination apparatus to an external remote terminal for evaluation,for example by a healthcare professional. The remote terminal may be acomputer, a laptop, a tablet device, or even a cell phone. In someembodiments, the external remote terminal may be disposed in a differentroom than the eye examination apparatus. In some embodiments, theexternal remote terminal may be disposed in another building, anothercity, another state/province, or even another country than the eyeexamination apparatus. In some embodiments, the eye measurement data maybe communicated via the Internet. In some embodiments, the eyemeasurement data may be communicated in real time, as it is processed bythe eye examination apparatus. In some embodiments, the eye examinationapparatus only communicates filtered eye measurement data which wasfiltered in operation 18700.

An operation 18900 includes the eye examination apparatus providinginformation messages via display device 2400 provided at an externalsurface of the housing to the subject and/or an observer who is withinsight of the display device. In some embodiments, such informationmessages may include advertisements or commercials, which may be in theform of images or video.

In some embodiments, advertisements may be displayed on display device2440 on an external face of housing 1100 when eye examination apparatus1000 is not in use. These advertisements can provide information abouteye examination apparatus 1000, can provide information about visionhealth insurance or other public services, or can simply be promotionalmaterial from paid sponsors. Furthermore, advertisements can be playedon the internal display (see FIG. 22) that is used for the subjectvisual target at any time during the examination. An example would beright after an objective refraction has been completed so that therefraction results can be used to ensure that the instrument willdisplay the informational content in a clear fashion.

In various embodiments, method 18000 may include additional operationsto those shown in FIG. 18. In some embodiments, the eye measurementapparatus may display a QR code (or bar code) with instructions on thevideo monitor instructing subject 10 to use their camera to sign up foran eye exam. The QR code or hyperlink that connects the potentialsubject with the instrument (or a network) in order to sign up for andpotentially initiate the eye examination.

In some embodiments, when before, during, and/or after a subjectencounter with an eye examination apparatus, the subject suppliespersonal information, including identification information, and maycomplete a patient intake survey. In some embodiments, this may beaccomplished by providing the eye examination apparatus with a webserverwhich may interact with the subject's mobile phone, tablet or laptop. Insome embodiments, a web service accessible via the internet whichhandles eye examination scheduling may provide these functions, ratherthan supplying each eye examination apparatus with a webserver.

FIG. 19 illustrates an example of a web page which may be displayed on asubject's cell phone before, during and/or after an interaction with theeye examination apparatus.

FIG. 20 illustrates an example embodiment for a workflow 20000 for aneye examination of an eye.

FIG. 20 illustrates operations (20010 and 20020) which occur when theeye examination apparatus is located in an eyecare clinic, operationswhich occur when the eye examination apparatus is an unattended kiosk(20110, 20120 and 20130), and operations which are common to bothsituations (all remaining operations).

An operation 20010 includes an eye examination subject, or patient,checking in at the front office of an eye care clinic at the time ofappointment.

An operation 20020 includes leading the subject to the eye examinationapparatus, and a health care professional (HCP) technician providesaudio cues to look at a target in the eye examination apparatus.

An operation 20110 includes an eye examination subject, or patient,walking up to a kiosk comprising an eye examination apparatus andchecking in to the kiosk using a smartphone app, and initiating an eyeexamination.

An operation 20120 includes a HCP logging onto a web portal via anexternal remote terminal.

An operation 20210 includes the subject standing in front of instrumentand receiving audio clues to look for the fixation target.

An operation 20215 includes the eye examination apparatus detecting thepresence of the subject, starting gross alignment with the subject'seye(s), and providing audio instructions to the subject.

An operation 20220 includes auto-aligning an optical system to thecorrect height for the subject, performing fine alignment forinterpupillary distance, estimating a working distance to the eye(s),and begin tracking the eye(s).

An operation 20225 includes performing an initial objective measurementof refraction, pre-compensating the target path by correcting for theinitially-measured refraction, making multiple refraction measurementsof the eye(s), capturing images of the anterior pupil of each eye, andtracking eye motion and head motion while compensating the target path.

An operation 20230 includes providing audio clues for the subject andmoving the target.

An operation 20235 includes the subject receiving instructions to watcha moving fixation target, and the subject watching the moving fixationtarget.

An operation 20240 includes an unseen infrared (IR) illuminationilluminating the fundus of the subject's eye(s) under a controlledsequence of gaze angles. Several images of different portions of thefundus may be processed and stitched together to build a larger image ofthe fundus.

An operation 20245 includes the eye examination apparatus either beingcontrolled by the HCP for a subjective refraction test (e.g., via atablet device), or running an automated algorithm (kioskimplementation), with the subject responding to standard yes/noquestions using voice recognition. Monocular subjective refraction foreach eye may be determined.

An operation 20250 includes a subject answering subjective questionsabout visual acuity for each eye, for example: “Which one is better? 1or 2?”

An operation 20255 includes the eye examination apparatus assembling eyemeasurement data or results and providing the assembled eye measurementdata/results to the HCP, either via a clinic internal network or HIPAAweb portal, and informing a subject and a remote HCP that the eyeexamination has completed.

An operation 20130 includes the HCP receiving patient data and theassembled eye measurement data/results.

An operation 20260 includes the HCP reviewing the assembled eyemeasurement data/results (e.g., subjective vs objective refraction,fundus imaging, etc.) and deciding whether the subject needs a manualrefraction or retinal examination.

An operation 20265 includes the HCP discussing the eye examinationresults in person or over a web portal, and providing the subject with aprescription.

An operation 20270 includes the HCP updating internal patient recordswith information from the eye examination, and potentially scheduling afollow-up eye examination.

FIG. 21 illustrates an example embodiment for a workflow 21000 for aneye examination apparatus to make a subjective (manifest) refractionmeasurement of an eye.

In FIG. 21, the following applies: ss=increment step size; max=maxtries; max_(OM)=OverMinus tries; OR=Objective Refraction; CR=currentrefraction; FR=final refraction; Thresh=convergence threshold; OMthresh=over-minus threshold. In an example: beginning ss=1.0D, cnt=0,cnt2=0 and beginning CR=OR.

Workflow 21000 uses voice recognition and captures subject facialresponses during a subjective refraction for post-measurement review bya Health Care Provider (HCP).

The starting point for the subjective examination is after the eyeexamination apparatus has captured an objective refraction for theeye(s). The objective refraction may be used as the starting point forthe subjective refraction measurement. The sphero-cylindricalcompensation may be added to the target path (e.g., also accounting forchromatic aberrations and for lane length). Each choice may be brieflypresented to the subject, e.g., for 3-5 seconds.

An example in English follow (in some embodiments, other languages maybe available).

In this example, the eye examination apparatus gives verbal instructionsto the subject (e.g., through a speaker) as follows:

Apparatus: “We will begin a subjective test now—please listen andrespond to questions.”

Apparatus: “Yes or no—Is the target clear to you now?” If the subjectanswers no, the eye examination apparatus may reperform the objectiverefraction measurement or select the most hyperopic objectivemeasurement result. If the subject answers yes, the algorithm proceedsto the next step, and moves on after two additional tries.

Apparatus: “You will now be presented with a choice of targets—pleasetell the instrument which option is better by answering with one, two,same, neither or repeat. Answer neither if neither choice of targets isclear. Answer same if both choices of targets are clear, and it isdifficult to determine which is better. Answer repeat if you would liketo see both choices again.”

FIG. 22 illustrates an example embodiment of an eye target 22000 whichmay be used to communicate with a subject.

To further prevent the need for touch screen responses and to assisthearing impaired subjects, messages and possible subject responses canbe displayed as words in the subject's preferred language or signlanguage, or as icons on the target screen. The eye examinationapparatus may use voice recognition to determine the subject's response,or the eye examination apparatus may determine the subject's responsebased upon which of the provided response areas on the display thesubject is fixating their eye(s) upon, and/or may interpret signlanguage or facial expressions to determine subject responses.

As disclosed above, an eye examination apparatus comprising amulti-function ophthalmic instrument for eye health and visionexaminations does not require the subject's head to be constrainedduring examination. It automatically and continuously aligns an internaleye measurement system to the subject's eye(s) during the measurements,regardless of normal subject motion. The optical paths for allmeasurements include a sufficiently large standoff to allow allmeasurements to take place with the subject standing comfortably distantfrom the housing of the instrument, including for example a protectivewindow separating the subject from the measurement module. The eyemeasurement system is capable of video rate measurements. Audio/visualcues may be provided remotely by the instrument, technician, orphysician prior to, during, and after the measurement(s). Byincorporating a housing with an easily disinfected smooth outer shell,and by eliminating the traditional headrest and chair, the apparatus canmeasure subject's eyes without the need for the subject to contact anyinstrument surfaces or to be in proximity to a technician or HCP duringthe measurements, thus greatly reducing the risks of crosscontamination.

While example embodiments are disclosed herein, one of ordinary skill inthe art appreciates that many variations that are in accordance with thepresent teachings are possible and remain within the scope of theappended claims. The invention therefore is not to be restricted exceptwithin the scope of the appended claims.

The invention claimed is:
 1. An apparatus, comprising: a processingsystem including a user interface; an eye measurement system includingan optical system, wherein the eye measurement system is configured tomake at least one optical measurement of an eye of a subject; a housinghaving the eye measurement system disposed therein, wherein the housingincludes an aperture for providing light to and from the optical systemand the eye while the subject is separated and spaced apart from thehousing and while the eye is not maintained in a fixed positionalrelationship with respect to the housing; an optical system movementarrangement which is configured to move the optical system; and anautomatic eye tracking arrangement which is configured to ascertain acurrent positional relationship of the eye with respect to the opticalsystem without human assistance, and in response thereto to control theoptical system movement arrangement to move the optical system into apredetermined positional relationship with respect to the eye withouthuman assistance, wherein the eye measurement system includes: at leastone objective refractive measurement device which is configured to makean objective refraction measurement of the eye via the optical system, atarget, and a mirror system disposed in an optical path between the eyeand the target for extending a length of the optical path, wherein theoptical path further comprises at least one optical element of theoptical system, and wherein the processing system is configured tointeract with the subject via the user interface and in response to theinteraction to adjust at least one parameter of the optical system tomake a subjective refraction measurement of the eye based on the subjectviewing the target.
 2. The apparatus of claim 1, wherein the opticalsystem includes a first lens, and wherein the automatic eye trackingarrangement includes a Lidar device which is configured to provide lightto the eye via the first lens and to receive returned light from the eyevia the first lens for determining a distance between the eye and thefirst lens.
 3. The apparatus of claim 2, wherein the optical systemincludes a pre-compensation section which is configurable to bring thetarget into focus on the subject's eye for making the subjectiverefraction measurement of the subject's eye, and wherein the distancebetween the eye and the first lens as determined by the Lidar device isemployed to adjust a position of at least one lens in thepre-compensation section to maintain focus and refractive correction forthe eye.
 4. The apparatus of claim 1, wherein the automatic eye trackingarrangement comprises: at least one light source configured toilluminate the eye; and at least one camera configured to receive animage of the eye, wherein the camera is configured to output image dataof the image of the eye to the processing system, and wherein theprocessing system is configured to control the optical system movementarrangement to move the optical system into the predetermined positionalrelationship with respect to the eye based on the image data.
 5. Theapparatus of claim 1, including a communication device, wherein thecommunication device is configured to communicate eye measurement datafrom the apparatus to an external remote terminal for evaluation.
 6. Theapparatus of claim 5, further comprising: at least one light sourceconfigured to illuminate the eye; and at least one camera configured tocapture images of the eye, wherein the processing system is configuredto execute a filtration algorithm for filtering the eye measurement dataprior to communication to the external remote terminal to reject atleast a portion of the eye measurement data when the portion of the eyemeasurement data is taken when the images of the eye fail to meetpredefined quality criteria due to at least one of: a full blink, apartial blink, an incorrect gaze angle, incomplete dis-accommodation,and a saccade.
 7. The apparatus of claim 1, further comprising astructured lighting device, wherein the structured lighting device isconfigured for at least one of: eye imaging, keratometry, eye motilitytesting, and slit lamp imaging of the eye.
 8. The apparatus of claim 1,further comprising: at least one light source configured to illuminatethe eye; at least one camera configured to capture images of the eye;and a visual cue generator for presenting to the subject a visual cuefor changing a gaze angle of the eye while capturing the images of theeye.
 9. An apparatus, comprising: a processing system including a userinterface; an eye measurement system including an optical system,wherein the eye measurement system is configured to make at least oneoptical measurement of an eye of a subject; a housing having the eyemeasurement system disposed therein, wherein the housing includes anaperture for providing light to and from the optical system and the eyewhile the subject is separated and spaced apart from the housing andwhile the eye is not maintained in a fixed positional relationship withrespect to the housing; an optical system movement arrangement which isconfigured to move the optical system; an automatic eye trackingarrangement which is configured to ascertain a current positionalrelationship of the eye with respect to the optical system, and inresponse thereto to control the optical system movement arrangement tomove the optical system into a predetermined positional relationshipwith respect to the eye; and a communication device, wherein thecommunication device is configured to communicate eye measurement datafrom the apparatus to an external remote terminal for evaluation,wherein the eye measurement system includes: at least one objectiverefractive measurement device which is configured to make an objectiverefraction measurement of the eye via the optical system, a target, anda mirror system disposed in an optical path between the eye and thetarget for extending a length of the optical path, wherein the opticalpath further comprises at least one optical element of the opticalsystem, wherein the processing system is configured to interact with thesubject via the user interface and in response to the interaction toadjust at least one parameter of the optical system to make a subjectiverefraction measurement of the eye based on the subject viewing thetarget, and wherein the communication device is further configured toreceive instructions from the external remote terminal for adjusting atleast one operating parameter of the apparatus.
 10. The apparatus ofclaim 9, wherein the optical system includes a first lens, and whereinthe automatic eye tracking arrangement includes a Lidar device which isconfigured to provide light to the eye via the first lens and to receivereturned light from the eye via the first lens for determining adistance between the eye and the first lens.
 11. The apparatus of claim9, wherein the automatic eye tracking arrangement comprises: at leastone light source configured to illuminate the eye; and at least onecamera configured to receive an image of the eye, wherein the cameraoutputs image data of the image of the eye to the processing system, andwherein the processing system is configured to control the opticalsystem movement arrangement to move the optical system into thepredetermined positional relationship with respect to the eye based onthe image data.
 12. The apparatus of claim 9, wherein the at least oneoptical measurement of the eye includes at least one of: a high orderaberration of the eye, a pupil response characteristic, an externalimage of the eye, intraocular pressure of the eye, a fundoscope image ofthe eye, a corneal topography of the eye, an optical coherencetomography of the eye, and a blink rate of the eye.
 13. The apparatus ofclaim 9, wherein the user interface includes at least a microphone forreceiving voice communication from the subject, and a speaker forproviding audio information to the subject.
 14. The apparatus of claim9, further comprising: at least one light source configured toilluminate the eye; at least one camera configured to capture images ofthe eye; and a visual cue generator for presenting to the subject avisual cue for changing a gaze angle of the eye while capturing theimages of the eye.
 15. A method, comprising: making at least one opticalmeasurement of an eye of a subject with an eye measurement systemincluding an optical system, wherein the eye measurement system isdisposed within a housing, wherein the housing includes an aperture forproviding light to and from the optical system and the eye while thesubject is separated and spaced apart from the housing and while the eyeis not maintained in a fixed positional relationship with respect to thehousing; and ascertaining, via an automatic eye tracking arrangementwithout human assistance, a current positional relationship of the eyewith respect to the optical system, and in response thereto moving theoptical system into a predetermined positional relationship with respectto the eye without human assistance, wherein making the at least oneoptical measurement of the eye includes: making an objective refractionmeasurement of the eye via the optical system, and interacting with thesubject via a user interface, and in response to the interactionadjusting at least one parameter of the optical system to make asubjective refraction measurement of the eye based on the subjectviewing a target through an optical path which includes a mirror systembetween the eye and the target for extending a length of the opticalpath, wherein the optical path further comprises at least one opticalelement of the optical system.
 16. The method of claim 15, wherein theautomatic eye tracking arrangement: illuminates the eye; receives animage of the eye at a camera; outputs image data of the image of the eyefrom the camera to a processing system; and controls an optical systemmovement arrangement to move the optical system into the predeterminedpositional relationship with respect to the eye based on the image data.17. The method of claim 15, further comprising communicating eyemeasurement data from the eye measurement system to an external remoteterminal for evaluation.
 18. The method of claim 17, further comprising:illuminating the eye; capturing images of the eye; and filtering the eyemeasurement data prior to communication to the external remote terminalto reject at least a portion of the eye measurement data when theportion of the eye measurement data is taken when the images of the eyefail to meet predefined quality criteria due to at least one of: a fullblink, a partial blink, an incorrect gaze angle, incompletedis-accommodation, and a saccade.
 19. The method of claim 15, furthercomprising providing information messages via a display device providedat an external surface of the housing to at least one of the subject andan observer within sight of the display device.
 20. The method of claim15, further comprising performing a slit lamp examination of the eye viaa slit lamp illumination source disposed within the housing.